Mold construction



Feb. 1s, 1941.- g., E, MCWANE 2,232,126

MOLD CONSTRUCTION Original Filed Jan. 17, 1956 #averi/75Min;

Patented Feb. 18, 1941 APxliaui caricia'.l

' 2,232,126 MOLD CONSTRUCTION Henry E. McWane, Lynchburg, Va.

Application January 17,1936, serial No. 59,607

l i Renewed June 26, 1939 11 Claims.

This invention relates to molds, and more particularly has reference to a construction for use in molds of the permanent type.

" Permanent molds heretofore have presented certain objections. Such molds have generally been of relatively slight longevity, principally in view of the fact that the gates for conducting the molten metal to the mold cavities are damaged by the hot metal through erosion. This has -been due to the fact that heretofore the molds and gates have usually been made of the same material, and in order to insure a retention of the metal in the molten state until all parts of the cavity were iilled, it has been necessary to make the molds and their gates of a metal having a relatively low heat conductivity. While this is obviously desirable insofar as the mold per se isi concerned, the use of a metal of low heat conductivity for the formation of the gate results in the erosion above-mentioned.

' On the other hand, if the mold and gate are made of a metal' of high heat conductivity in order to prevent erosion of the gate, then there is a tendency for the molten metal lto solidify before all parts of the mold cavity are lled with the molten metal.

To overcome the above disadvantages is one of the objects of my invention.

Another object of my invention is to provide Q0 a mold in which Ithe castings will be fully formed, and without commercial imperfections, and which will have va long life.

A further-object of my invention is to provide a mold construction which, at the point where damage is most likely to occur, will be highly resistant to erosion by the hot metal, yet which is simple to construct and easy to repair or replace.

A still further object of my invention is to provide Aa mold construction in which the gate is conductivity, and in which the mold cavity is formed of metal having low heat conductivity.

With these and other objects in view, which may be incident to my improvements, the invention consists in the parts and combinations to be hereinafter set forth and claimed, with the understanding that the several necessary elements comprising my invention may be varied in con- 50 struction, proportions and arrangement, without departing from the spirit and scope of the appended claims.

In order to make my invention more clearly understood, I have shown inthe accompanying 55 drawing means for carrying the same into pracformed'of a metal having a relatively high heat tical effect Without limiting the improvements in their useful applications to the particular constructions, which for the purpose of explanation, have been made the subject of illustration.

In `the drawing, 5

Figure 1 isaI plan view of one half of a mold constructed in accordance with my invention;

Figure 2 is a sectional view of an assembled mold along the line 2-2 of Figure l, looking in the direction of the arrows; 10

Figure 3 is a view along the line 3 3 of Figure 1, looking in the direction of the arrows.

- Referring more particularly to Figure 1, in whichlis disclosed one of the halves of a mold, there is depicted the usual base member I on which are mounted the mold block 2 and gate block 3. As best shown in Figure 2, the blocks 2 and 3 are secured to the base by means of bolts 4 which pass through lugs 5 upon the blocks and which are screw threaded into the base member I. 20

The mold disclosed in Figure 1 is for the formation of a mold board, and forthis purpose the block 2 is provided with a depression 6 of the necessaryshape. This depression, together with a. corresponding depression in the opposed block 2, forms a cavity 1, as best shown in Figure 2. A channel depression 8` extends from the depression 6 to the edge of the block, likewise forming, with a similar depression in the opposed block, a channel 9. The molten metal is introduced to the 30 cavity I through the channel 9.

The gate II (Figure .2) is formed by corresponding channels I2 in the gate block 3, and the gate l2 is branched to form branch gates IZ-A and I2B extending to the respective channels 9; 3 It is of course obvious that if the base member carries but a single mold, the branching of the gate I I is dispensed with.

As above-mentioned, it is desirable that the molten metal be maintained in a molten condition until theentire cavity-1 is lled, and to accomvplish this I employ as the material of mold block 2, a metal having a relatively low heat conductivity in order to prevent anyloss of heat from 45 the molten metal. While various metals may be employed for this purpose, I prefer cast iron. It will be appreciated that cast iron is rigid and inflexible and therefore is not subject to any appreciable warpage during the heating and cooling may be formed by making the block 2 of two pieces 2-A and Z-B, and suitably welding the same, as at Il. A suitable lining I5 may be employed in the water jacket, in order to prevent the possibility of water coming in contact with the molten metal in the event of a. crack in theV mold. o

The water jacket, by virtue of its cooling effect,

I prevents undue wear of the mold by excessive heat. It is of particular value where the mold is being used for successive casting operations, in that it serves to lower the temperature of the mold between each pouring. This feature has been more fully described in my copending application Serial No. 52,248. The above serves to retain the heat of the molten metal. and at the same time prevents undue wear of the mold by excessive heat. l

While it is desirable to prevent the loss of heat of the metal in the mold cavity, I do nevertheless prefer to use a metal which can be maintained at a relatively low temperature in rapid production, in view of the fact that the greatest damage from heat appears in the gate. To prevent such damage, I make the gateblock 3 of metal having a relatively high heat conductivity, such, for instance, as electrolytic copper. In actual practice, I have found electrolytic copper to be particularly eiicacious, and it may be that this is accounted for by certain properties other` than its-heat conductivity. However, I believe that its principal value resides in its property of dissipating the heat of the molten metal, and that therefore other metals of relatively high heat conductivity may be used in lieu of electrolytic copper.

I nd it preferable to provide a water jacket 'i6 for the gate block3 also. This water jacket may be formed in the same way as the jacket for the mold block, namely, by making the gate block from two pieces of metal 3-A and 3-B and welding the same together as at I1. It will be.

appreciated that suitable inlets and outlets may be provided for both water jackets I3 and I6.

The advantages of my invention are believed to be apparent from the foregoing. There is a decided increase in the eiective life of molds constructed in accordance with my invention with no sacrifice in the castings that are produced therein. By making the gate block of metalhaving'a high heat conductivity, erosion of the gate by the molten metal passing therethrough is prevented. At the same time, the metal is not factors of the cast article. In general, however, the heat dissipation properties of the gate block should be greater than those of the mold block in order to prolong the eiective life of the gate and at the same time permit penetration of the metal to all parts of the mold cavity.

l While I have shown and described the' preferred embodiment of my invention, I wish it to vbe understood that I do not confine myself to the precise details of construction herein' set forth by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

I claim:

1. A mold construction comprising a mold block formed from a metal of relatively low heat conductivity, and a gate block in association therewith formed from a metal of high heat conductivity. I

2. A mold` construction, and in combination, a mold block formed froma metal of relatively low heat conductivity, with a gate block formed from a. metal of high heat conductivity, and 25 means for increasing the rate of cooling of the gate.

3. A mold construction comprising a cast iron mold block and a gate block of a metal of high 30 'electrolytic copper water-jacketed gate, a mold inassociation therewith of cast iron, and waterjacketed means for cooling said cast iron mold parts.

6. In combination in a mold construction, a copper gate, a mold in association therewith of cast iron and water jacketed means for cooling said cast iron mold parts.i

'1. A mold construction comprising a cast iron mold block and a gate block of copper.

8. A mold construction comprising a gate of copper, and a mold which has a lower rate of cooling than the gate.

9. A mold constructionl comprising a gate of electrolytic copper, and a mold which has a lower rate of cooling than the gate.

10. A mold construction comprising a gate of electrolytic copper, a water jacket for the gate to increase its rate of cooling, and a mold of a lower rate of cooling than the gate.

1l. A mold construction .comprising a gate of electrolytic copper, a water-jacket for the gate to increase its rate of cooling, a mold, a waterjacket for the mold, said mold with the waterjacket. having a lower rate of cooling than the electrolytic copper gate and ,the water-jacket combination.

. HENRY E. MCWANE. 

